Contact

Porträt Prof. Dr. Kvashnina, Kristina; FWOS

Prof. Dr. Kristina Kvashnina

Head of the Synchrotron Science Department
Responsible for the BM20 (ROBL) beamline at ESRF
k.kvashnina@hzdr.de
Phone: +33 476 88 2367

Department of Synchrotron Science

Research

The Department of Molecular Structures conducts synchrotron-based research, offering a robust toolkit for scientists investigating materials containing actinides and lanthanides.

Experiments take place at the Rossendorf Beamline of The European Synchrotron (ESRF), in Grenoble (France) which is specifically dedicated to the actinide science and research on radioactive waste disposal. The beamline consists of four experimental stations -XAFS, XES, XRD-1, XRD-2:

XAFS station with fluorescence and transmission detection for X-ray Absorption Fine-Structure (XAFS) spectroscopy, including (conventional) X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray absorption fine-structure (EXAFS) spectroscopies
XES with a 5-crystal Johann-type spectrometer for high-energy-resolution fluorescence-detection X-ray absorption near-edge spectroscopy (HERFD-XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) measurements.
XRD-1 station with a heavy-duty, Eulerian cradle, 6-circle goniometer for (high-resolution) powder X-ray diffraction (PXRD), surface-sensitive crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements
XRD-2 station with a Pilatus3 x2M detector stage for single crystal X-ray diffraction (SCXRD) and in situ/in-operando PXRD measurements.

Our research provides detailed insights into the structural and electronic properties of actinide and lanthanide-containing materials across various scientific disciplines, including physics, chemistry, environmental science, and geoscience. We study fundamental electron interactions, bonding properties, probing the local structures and oxidation states of complex systems. Data analysis is performed with the help of electronic structure calculations.

EXAFS, HERFD-XANES, XES and RIXS is not restricted to crystalline solids, but can be applied to a wide range of samples, to derive information on e.g. aqueous speciation, complexation with dissolved inorganic ligands like chloride, sulfate or nitrate, complexation with organic ligands like acetate or humic acid, interaction with bacteria and plants, sorption to mineral and rock surfaces for actinides an other metals and metalloids. Due to the high penetration depth of the employed hard X-rays, the methods are suited to study chemical reactions in-situ/in-operando, for instance at very low or high temperatures, under special atmospheres, or under electrochemical potentials.

More about Rossendorf Beamline

Latest publication

Reproducing the Thermophysical Properties of Irradiated FR-MOx Fuel with Surrogate Materials

Martin, P.; Martinez, J.; Staicu, D.; Vlahovic, L.; Prieur, D.; Audubert, F.; Clavier, N.

Abstract

Nuclear energy is expected to play a key role in future low-carbon energy systems, but its long-term viability depends on advanced fuel cycles capable of recycling valuable materials from spent fuel. Fast reactors operating with mixed uranium and plutonium oxides (MOx) are central to this strategy, but their safe deployment requires accurate knowledge of the thermophysical properties of the fuel under irradiation. However, such data remains extremely scarce, as irradiated MOx is difficult to obtain, highly radiotoxic and inaccessible for high-temperature measurements. This lack of experimental data limits the validation of fuel performance models and constrains the assessment of the safety margin to melting. Here we show that specially designed surrogate materials – SIMMOx – can faithfully reproduce the thermal behaviour of irradiated MOx fuel without any irradiation, solely through the controlled incorporation of chemically representative fission products (FPs). We have demonstrated that dissolved FPs significantly reduce thermal diffusivity and conductivity, while metallic and oxide precipitates have a negligible impact, impacts that are currently impossible to study specifically on irradiated MOx. The predominant role of dissolved FPs was demonstrated for the first time directly by thermodynamic incorporation alone, reproducing the effect normally produced by years of irradiation in a fast reactor. These results clarify the mechanisms governing thermal transport degradation in MOx fuel and improve the predictive models developed for irradiated fuels. More broadly, they provide a new experimental route to study fuel behaviour at high temperature without the constraints associated with irradiated materials. This approach opens the way to systematic studies over a wide range of burnups and compositions, offering a practical framework to support the qualification of fuels for next-generation fast reactors.

Involved research facilities

Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265

Related publications

DOI: 10.1107/S1600577520014265 is cited by this (Id 42832) publication

Journal of Nuclear Materials (2026)

Permalink: https://www.hzdr.de/publications/Publ-42832

More publications

Team

Name	Bld./Office	+49 351 260	Email
Head
Prof. Dr. Kristina Kvashnina	ROBL/21.6.04	+33 476 88 2367	k.kvashnina@hzdr.de
Employees
Name	Bld./Office	+49 351 260	Email
Dr. Lucia Amidani	ROBL/14.1.04	+33 476 88 1982	l.amidanihzdr.de
Dr. Nils Baumann	ROBL/21.6.03	+33 476 88 2849	n.baumannhzdr.de
Jörg Exner	ROBL/BM20	+33 476 88 2372	j.exnerhzdr.de
Dr. Christoph Hennig	ROBL/21.6.02a	+33 476 88 2005	c.hennighzdr.de
Dr. Eleanor Sophia Lawrence Bright	ROBL/14.1.03	+33 476 88 2462	e.lawrence-brighthzdr.de
Dr. Damien Prieur	ROBL/21.6.03	+33 476 88 2463	d.prieurhzdr.de
Dr. André Roßberg	801/P316	2758	a.rossberghzdr.de
Anne Thielen	ROBL/21.6.02a	+33 476 88 2232	a.thielenhzdr.de
Dr. Sami Juhani Vasala	ROBL/14.1.01		s.vasalahzdr.de